On Oct 4, 2014, at 4:34 AM, Murray Brown
<m.brown.nsb@xxxxxxxxx<mailto:m.brown.nsb@xxxxxxxxx>> wrote:
I got the impression during all my tests that there may be a complication due
to the relative spatial extents of the two objects, the map and the topo. Do
you or the IDV folks know if there is some limitation/restriction on the
success of this formula, due to spatial relationship? And could spatial
subsetting (although I did not use it) play a role?
Murray,
That’s a good question, and though I don’t know the answer, I haven’t had any
trouble with at least some model output files whether I accepted all the region
defaults, specified a custom region using an elastic box, or selected “Match
Display Region”.
The exception seems to be when I try to use GFS model analyses.
I just tried loading a GFS analysis (a local file acquiring using our RAMADDA
server: see Catalogs: http://virga.sfsu.edu:8080/repository/thredds >
14100412_gfs2_F00.grb, for example) and plotting hi-res state boundaries. If I
accept the region defaults for both the map data and the topography (which is
geopotential height of ground and water surfaces) and plot hi-res state
boundaries, then I get a 3D map for the eastern part of the US, but it’s cut
off west of there and the topography doesn’t make sense for the eastern U.S.
(or anyplace else that I know). Moreover, I’m unable to improve on that result
using GFS data from another model run or by selecting custom regions or by
selecting “Match Display Region". In fact, when I specify a custom region or
select “Match Display Region”, I get no map plot at all and the map plot color
table is labeled “missing gpm”.
In contrast, when I tried a 40 km NAM forecast, an 80 km NAM forecast, a RUC
forecast, and a 10 km WRF model forecast, all using the same hi-res state map
data, all plotted just fine, regardless of whether I accepted the default
regions or specified “Match Display Region”.
Seems like the IDV is having a problem reading the GFS model files correctly in
this context. (But even with the GFS data, as my screen shot yesterday showed,
I get separate prompts for the map data and the topography, and both offer
correct choices to choose from, which differed from what you had reported
seeing.)
— Dave
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